1. Field of the Invention
The invention relates to a method for actuating a wheel brake assembly, in particular an electromechanical wheel brake assembly or a mechanical system involving friction and having spring elasticity.
2. Description of the Prior Art
For the sake of clear illustration, the invention will be explained below concretely in terms of the actuation of an electromechanical wheel brake assembly. However, the invention is not intended to be limited to electromechanical wheel brake assemblies; for instance, the method of the invention is applicable to hydraulic or pneumatic wheel brake assemblies, especially if they are actuated by external force, and generally to mechanical systems involving friction and having spring elasticity.
Electromechanical wheel brake assemblies are known per se. For example, see German Patent Disclosure DE 42 29 042 A1. The known electromechanical wheel brake assemblies have an electric motor, whose rotary motion is transmitted by a gear to a rotation/translation conversion gear, typically a spindle drive, with which a friction brake lining can be pressed (tightening) against a brake body, connected in a manner fixed against relative rotation to a vehicle wheel, such as a brake disk or a brake drum, and lifted again (releasing). To convert the rotary motion of the electric motor into a translational motion for exerting pressure on the brake lining, a cam can for instance also be used. It is also known to embody a rotor of the electric motor as a nut of the spindle drive and to dispense with the gear between the electric motor and the spindle drive.
For braking, in the known electromechanical wheel brake assemblies the electric motor is supplied with current in the tightening direction, until a desired a braking force is reached. The braking force can be increased until such time as a quasi-static terminal state is attained, at which a torque of the electric motor, at maximum current supply, no longer suffices to increase the contact pressure of the friction brake lining against the brake body any further.